Locomotive stoker



@CL 28, 193.0. Y N. M. LOWER 1,779,609

LOCOMOTIVE STOKER Filed Deo. l2, 1925 3 SheetsSheet l Get. 28, 1930.

N. M. LOWER LOCOMOTIVE STOKEH 3 Sheets-Sheet 2 Filed Dec. l2l 1925 JIA vill/lill] A il Oct. 28, 1930. N. M. LOWER LOCOMOTIVE STOKER Filed Deo. 12, 1925 3 Sheets-Sheet 3 ovneys www mt;

' Patented Oct. 28, 193e NATHAN n. LOWER, orV PITTSBURGH, PENNSYLVANIA, AssIveNon, BY MEsNgE ASSIGN- UNITED sTATEs PATENT OFFICE MENTS, T THE STANDARD STOKEB COMPANY INC., OF NEW YORK, N. A COR- PORATION OF DELAWARE Locoiuorrvr:y s'roxnn Application :Bled December 12, .1925. Serial No. 75,028.

-This invention relates to locomotive stokers and contemplates a steam engine driving fuel conveying mechanism that may after checking or stopping the piston until abnormal cylinder.

The invention is most useful where the inlet port is open during practically the entire stroke of the piston; for retarding or stoppressure has accumulated in the l2o ping the piston permits the pressure in the l cylinder' to build up, and when the augmented 4power overcomes the obstruction, the pis-l ton and attached parts assume the character of a proJectile of such energy that normal load and the 'usual cushioning devices cannot prevent destructive strains either on the piston and the cylinder at the end of the stroke, or upon the entire mechanism when a second clog occurs during the samestroke.

This is -partly dueto the fact that retarding I thepiston permits the normal pressure on the exhaust side to leak away and thus, to a greater or less extent, eliminate the normal cushion. The invention is of especial advantage where the thrust of the piston is transmitted to .the conveying mechanism without the intermediary of a crank shaft.

' The preferred form of the invention'is illustrated in the accompanying drawings, in

which Fig. 1 is ,a rear elevation with parts broken away to show interior mechanism;

Fig, 2 i@ n. section taken on the line 2-2 of Fig. 1; l

Fig. 3 is a section taken on theline 3-3 of Fig. 2

7 Fig. 4 is a bottom plan view of the engine cylinder;

Fig. 5 is a diagrammatic sectional view showing the several valves and the piston rod with their axes lying in one plane, in order to show in one figure the various passages and the manner of controlling them.

Fig. 6 is a sectional view taken on the 6.-'6 of Fig. 5,

Fig. 7 is a partial section taken on lthe lline 7-7 of Fig. 6.

' Fig. 8 is a side elevation of the Stoker with parts broken away, and

Fig. 9 is a longitudinal section correspondline ing to Fig. 5'through a fragment of an engine showing a modified form.

Referring to F ig. 1, 10 and 11 indicate the upwardly and outwardly inclined casings of theI elevating conveyors in which are mounted the elevating screws 12 'and 13, that deliver the coal to distributing'mechanism 14 by which it is scattered over the grate. Coal is brought from the tender to the locomotive b `a transfer conveyor, including the-troug 15 and thetransfer screw 16,

-mounted therein.

The three screws are driven by a single reciprocating rack 17 mounted in a casing 18 at the bottom of a casing 19 that forms a juncture between the transfer conveyor and the elevating conveyors. One'set of teeth 20 on the rack `l7 meshes with gears 21 and22 on shafts 23 and 24, extending through the hollow screws 12 and 13 and projectin above the top of the casings 10 and 11. 't their upper end shafts 23 and 24 are equipped with ratchet wheels 25 which engage pawls 26 and 27 carried by heads 28 secured to the.

upperends of the screws 12 and 13. .The pawls 26 and 27 are urged towards engagement with the ratchet wheels 25 by springs 29 and fingers 30 carried Vby hubs 31, projecting between the pawls 26 and 27, permittmg one of them to engage the ratchet while the other remains idle, or holding both of them idle according to the position of the hubs, which slide up and down on the reduced portions 32 of the shafts 23 and 24. The fingers 30 are4 provided with inclined slots 33 which cooperate with pins 34 carried by the heads 28 and serve to'rotate the hubs as theyare moved lengthwise along the shafts. I

When the rack 17 moves forward, or to the right, in Fig. 1, it will rotate the shafts 2.3 and 24 in one direction, and if the pawls 26 and 27 are in the proper position that rotation will be communicated to the elevating screws.

When the rack moves backwardly, or to the left, in Fig. 1, it willy rotate the shafts 23 and 24 in the opposite directions, but unless the pawls have been shifted the elevating screws will not be rotated.

By shifting the pawls the direction of rotation of the screws 12 and 13 can be reversed, and in this way a clog can-be released.

In the stroker here illustrated it is con# templated that the screw 12 will be rotated to elevate the coal w'r en the piston moves to the left and the screw 13 will be rotated to elevate coal when the piston moves to the right, thus providing alternate delivery by the two elevators.

A second set of teeth on the rack 17 meshes with the gear 36, on a shaft 37, equipped with a ratchet'wheel 38 cooperating with pawls 39 and 40 carried by a head 41 connected with the transfer screw 16 through the shaft 2 and the gearing 3, (Fig. 8). The pawls 39 and 40 are urged into e11- gagement with the ratchet wheel 38 by springs and are controlled by shifter fingers 42, substantially the same as those described in connection with the elevating screws and permitting the transfer screw to be driven forwardly or reversed, or allowed to remain idle, as occasion may require. In the stoker shown, the transfer screw is driven forward with the. elevating screw 12 as the piston moves to the right.

In this preferred construction power to drive the rack 17 is furnished by a single cylinder' 43, equipped with a piston'44, having its piston rod 45 operatively connected with the rack 17. Steam is suppliedto and exhausted from the cylinder by passages 46 and 47 which are Connected with the opposite ends of the cylinder by large ports 48 and 49, about a piston thickness from the cylinder heads 50 and 51, and by small ports 52fand 53 at the adjacent faces of thecylinder head.

When the piston is moving forward, orQ

to the right, in Figs. 1, 4 and 5, it closes the large port 49, trapping the remainder of the exhaust steam and forcing it to escape through the small port 53, thus forming a cushion to prevent violent contact between the piston and the cylinder head 51. When the distributing valve is shifted livesteam enters the small port 53 and starts thelpiston towards the left slowly. After the piston has -moved its width the port 49 is opened admitting steam freely, whereby the piston is driven rapidly until the port -48 is closed and the vtrapped exhaust steam cushions the piston, as described, in the other end. Additional ports controlled by check 57, whose position is regulated by a control valve 58 operated b the valve stem 59 having shoulders 60v an 61 cooperating with the plate 62 on the piston 44.

, The valve 57 is operated by differential pistons 63 and 64 mounted in cylinders 65 and 66, the adjacent ends of which communicate with the steam box 67 in which the valve`57 reciprocates. The lower end of the cylinder 65 is constantly connected with the exhaust by 'a passage 68. The upper end of the cylinder 66 is connected with the control valve cavity 69 by a passage 70 which enters the cylinder 66 through the end wall thereof, and a passage 71 that enters through the side wall adjacent to the end wall. The control valve cavity 69 is constantly connected with the steam box` by passage 72 and is also connected with the exhaust by passage73, which is alternately opened and closed by the control valve.

. In Fig. 5 the controll valve has closed the passage and connectedthe passages 71 and 73 which, in effect, puts the upper end of the 'and receives live steam.

When the piston 44 continues to move to the left in Fig. 5, the plate 62, striking the shoulder 60, will shift the valve 58, opening the passage 70 and closing the passage 71. This admits live steam to the upper end of the cylinder 66 and forces the valve 57 down' wardly, connecting the passage 47 with the steambox and the passage 46 with the exhaust passage 56. When the piston lmoves to the right end of the cylinder in Fig. 5, the plate 62 will strike the shoulder 61 and shift the valve back to the position shown in Fig. 5.

The passage 70 will again be closed and the Y The transfer conveyor is `usually equipped withaa Crusher 4 against which the transfer screw forces, large lumps; of coal to reduce them to proper size. The valve mechanism described keepsy the supply ofilive steam open throughout practically the entire stroke of the piston. Hence, when the. Crusher engages a large or tough lump of coal, or a clog occurs in some. other part of the stoker, the piston is checked, the pressure behind the piston builds up, and the pressure in front of the piston decreases. When the lump breaks vor the clog yields and the load is thus' reduced to normal, the piston is urged fora ward by an abnormal pressure which frequently istoo great forthe normal load to control in the absenceof normal cushion of exhaust steam. If a second clog occurs before the end ofthe stroke, the driving gear is subjected to terrific strains, which often be,

. escape of the exhaust steam during the delay of the piston.

In the preferred form the communicating passage-.connects the parts 48 and 49 and is controlled by a valve which yields when the pressure `in one end of the cylinder exceeds a selected limit.

The valve comprises a casing reduced and threaded at 76 to fit a tapped opening 77 communicating with the passage 46, opposite to the port 49. A chamber 78 in the casing has an inlet passage 79, equipped with a valve seat 80 normally closed by valve 81, having cruciform guides 82 lnounted in the inlet 79. The chamber also .has a plurality of aligned outlets 83 back of the valve, one of which re- 'l lceives a pipe 84 Connected with a nipple 85 seated in a tapped `opening 86 in communication with the passage 47, opposite to the port 48. The other opening is normally closed by a plug 87.

The end of the casing 75, opposite to the inlet 79 is formed by a cap 88,'.secured to the casing by studs 89. A spring 90 extends y between' the cap and the valve 81'and resists the opening of, the valve with a selected force. The valve and the cap are provided with guides 91 and 92 to hold the spring in place. The pressure of the spring may be regulated by inserting washers between the spring and the cap, or between the cap and the casing, as occasion may-require.

The valve 81 remains closed as long as the pressure within the working end of the cylin- 'der does not exceed a' selected limit. As soon vthe exhaust steam.

The opening of the valve will vary with the pressure in the working end of the cylinder and thus vary the cushion provided. The 7 passage provided by the pipe 84 and the yielding valve may be varied to meet individual conditions, but ordinarily it should be of the same capacity as the passages 46 and 47, when the valve 81 is completely open.

In order to prevent waste of steam in filling the auxiliary passage to no effect, it may be equipped with a check valve 98.

The cap 88 is equipped with inclined -passages 93 connecting the chamber 78 with a drain 94 controlled by a ball valve 95. The ball is mounted in an enlarged bore 96 closed by a plug'97 opposite to the drain 94. The normal position of the valve is shown in Fig. 6, in which the drain94 is open to permit the escape of water. AS soon as steambegins to escape the valve will seat and close the drain 94. P

With the stokerhere shown lthe transfer conveyor and the left elevator will make a repair and also permitsthe invention to be applied to existing structures by merely drilling and tapping the cylinder walls at the proper places.

\Where' preferred, however, a somewhat simpler arrangement can be made by extending therauxiliary passage through the piston and mounting the valve therein. In Fig. 9, where such a structure is illustrated, the casing of the valve is formed by a bore 99 in the pistpn whichisthreaded at one end to receive a valve seat 100 and at the other to receive a perforated cap 101 between which the spring 102 and the valve 103 are mounted. This modified structure also provides for cushioning both strokes of the pist-on. lThe upper valve 103 will operate on the forward or right stroke of the piston and the lower valve will operate on theleft stroke of the piston. Y f

Use has been made of Aspecific description and illustration in order to disclose the invention, but it is intended that nothing contained herein shall unnecessarily limit the following claims, or require a construction thereof that would permit the substance of the invention to be used without infringement. Y

I claim as my invention:

1. In a locomotive stoker, a reciprocating 'engine including a piston, a cylinder receiving the piston,`steam passages communicating With said cylinder at points spaced from each end thereof for admitting and exhausting steam,-valve mechanism for controlling said ports and operated by said piston, passages at each end of said cylinder in communication,

with said first-named passages respectively, a passage adapted to connect the ends of said cylinder on opposite sides ofthe piston, a

Vvalve in the passage subjected to live steam and resilient means tending to close said valve against such pressure, saidfvalvel opening only on the return of said piston when the pressure in said cylinder reaches a predetermined maximum.

2. In a locomotive Stoker, the combination of fuel advancing means, an engine for driving said means and including a cylinder, a

- piston reciprocating therein, passages communicating with ports inthe cylinder at points spaced from each end thereof to admit and exhaust steam, means controlled by the operation of said piston for supplying steam` only and a spring normally .holding said valve closed. e

' 3. In a locomotive Stoker, the combination of fuel advancing means, anlengine for driving the same including a cylinder, a piston therein, means controlled by theoperation of said piston for supplying steam-alternately to each end of said cylinder substantially during theentire respective strokes of said \piston, passages communicating with the cylinder'at points spaced from each end thereof to admit and exhaust steam, comparative- 1y small passages communicating with said cylinder adjacent each end thereof, a passage connecting the cylinder on opposite sides of the piston, a 4pressure-sensitive valve'normal- 1y closing the last mentioned passage.

4. In a locomotive Stoker, the combination of fuel advancing means, an engine for driving the same including 3a cylinder, a piston,

therein, passages communicatingv with the cylinder at points spaced from the ends thereof to admit steam thereto and exhaust, the same therefrommeans controlled by the o'peration of said piston for supplying steam in rear of said piston substantially during 4the o entire stroke of said piston, a plurality of passages of small diameter between the ends from the ends thereof to admit ,steam to said cylinder and exhaust the same therefrom, means controlled by the operation of said enginefor supplying steam alternately to each en'd Yof said cylinder substantially during the entire respective strokes of said piston, communicating passages between the ends of the cylinder and said first-named passages, a' passage in communication with said ports including a casing attached to the cylinder and open to one end thereof, said casing havin that end o? the cylinder, a valve for saidseat, yielding means normally holding the valve on said seat, a fitting connecting with the other end of the cylinder and piping connecting said fitting and casing behind said valve.

6. Ina locomotive Stoker, the combination of fuel conveying means, an engine for driving the sameincluding a cylinder, a piston reciprocating in the cylinder, means for supplying steam alternately to each end of said cylinder substantially during the entire respective strokes of said iston, steam passages communicating with the cylinder at points removed from the ends thereof, respectively, to -admit `and exhaust steam, passages ,for placing the ends of said cylinder in.' commun-ication with said first-named passages, respectively,/andmeans for admitting steam in front of the piston when the pressure behind the piston exceeds a predetermined limit.

In testimony whereof I affix my signature. NATHAN M .LOWERl a valve seat facing away from ilo 

